The invention relates to computer aided material requirements planning and, more particularly, to digital data processing systems for monitoring and controlling manufacturing processes.
The art has only introduced digital data processing systems for aiding manufacturers in supervising and directing the production of goods. International Business Machines, Inc., for example, markets the MAPICS and COPICS systems for simulating, to a limited extent, discrete manufacturing processes. These systems are understood to operate by constructing models of the manufacturing process based upon the traditional bill of material and related routing concepts. Similar discrete manufacturing simulation and modeling systems are marketed by Arthur Anderson, PCR, and SSA.
In the modeling of bills of material, designers of the prior art material requirements planning (or "MRP") systems attempt to represent relations between produced goods and consumed articles on one-to-one or one-to-many bases. That is, the designs base their systems upon models in which users may define relationships such that a single produced good may relate to one consumed article (i.e., "one-to-one" relationship) or, alternatively, to plural consumed articles (i.e., a "one-to-many" relationship).
These sorts of relationships are readily visualized in a simplistic model of motorcycle manufacture. Here, a single produced good, a motor bike, may be assembled by combining multiple component sub-assemblies, e.g., a power assembly and a running assembly. These sub-assemblies, in turn, may be constructed from their own component sub-assemblies. For example, the power assembly may be constructed from an engine and a power train. While, the engine itself may be assembled from a housing containing a fuel-air system, an ignition system, a feedback system, and a lubrication system.
The second aspect of prior art CAM systems calls for the independent modeling of materials routing slips. In this aspect, the prior systems characterize movement of individual sub-assemblies from location to location, independent of those relations which may be represented by the corresponding bill of materials model. Thus, a routing slip model for the construction of a motorbike may represent the necessity of having two particular components, e.g., the exhaust manifold and handlebars, available at the start of the assembly process, even where, in reality, these parts are needed at different times of the manufacturing process.
A drawback of the prior art techniques resides in their inability to model the full range of manufacturing processes. Although specifically designed to aid in the production of discrete manufactures, e.g., motorbikes, telephones, etc., the systems fail to provide mechanisms permitting modeling of more than the most rudimentary aspects of such production. Moreover, with respect to the production of repetitive and process manufactures, e.g., petrochemicals, foods, etc., the prior art techniques prove almost wholly inapplicable. As discussed below, the prior art techniques are unable to model with any degree of reliability the operation of manufacturing processes of the type represented, for example, by a petroleum refinery, where a single consumed resource, crude oil, is used to produce a plurality of petrochemical products and by-products.
An object of this invention, therefore, is to provide an improved system for manufacturing requirements planning.
More particularly, an object of the invention is to provide a digital data processing system permitting the monitoring and control of process and repetitive manufactures, as well as discrete manufactures.
Another object of the invention is to provide a digital data processing system capable of accurately modeling and simulating the aforementioned manufacturing processes and to provide accurate scheduling, cost accounting, and reporting facilities.
These and other objects of the invention are apparent in the description which follows.